JP2940944B2 - Flow control valve device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow control valve device, for example, a spool valve device that switches between supply and discharge of oil to and from a hydraulic cylinder for a hydraulic suspension hydraulic cylinder of an automobile, and that controls a flow rate. .

[Prior Art] In a spool valve device for switching oil supply and discharge to a hydraulic cylinder for a hydraulic suspension of an automobile and controlling flow rate according to a conventional technique, as shown in FIG. A valve sleeve 3 having a length of about half of the hollow hole 2 is fitted and fixed to the right half of the hole 2, and a valve spool 4 is further slidably fitted in the valve sleeve 3 in the axial direction. The left end of the hollow hole 2 is the valve housing 1
The right end is hermetically closed by a lid plate 6 attached to the valve housing 1 by a cup-shaped screw lid 5 screwed into the valve housing 1 in an adjustable manner.

On the outer peripheral surface of the valve sleeve 3, annular grooves 7, 8, 9 are formed at three positions at intervals in the axial direction, and each annular groove 7, 8, 9 is formed.
A plurality (two in the example in the figure) of slits 10, 10; 11, 1 penetrating in the radial direction from the bottom of the valve sleeve 3 toward the inner peripheral surface of the valve sleeve 3.
1; 12,12 are formed equally on the circumference.

The valve spool 4 is provided with a first piston portion 13, a second piston portion 14, a first land portion 15, a second land portion 16 at both ends, and a first annular groove portion 17 and a second annular groove portion 18 therebetween. ing. The first piston portion 13 side of the valve spool 4 (third piston
The end (left side in the figure) forms an extension 19 and projects into the hollow hole 2. A flanged nut portion 20 is screwed to a tip of the extension portion 19, and one surface of the flange of the flanged nut portion 20, the end surface of the valve sleeve 3, the other surface of the flange of the flanged nut portion 20, and the cup-shaped screw cap 5. Compression coil springs 21 and 2
2 is fitted.

Slits 10,10; 12,12 of valve sleeve 3 and valve spool 4
The first land portion 15 and the second land portion 16 are formed so as to have zero lap when neutral. That is, the opposing edges of the slits 10, 10 and the slits 12, 12 coincide with the opposing peripheral edges of the first land portion 15 and the second land portion 16 in the neutral state.

The valve housing 1 is formed with respective passages 23, 24, 25 communicating with the annular grooves 7, 8, 9 of the valve sleeve 3, a pump P is provided in the passage 23, and a hydraulic cylinder for suspension of a vehicle is provided in the passage 24. C are connected by pipes, respectively. A fixed throttle (orifice throttle) 25a is provided in the passage 25 to apply back pressure in order to prevent cavitation, and an oil tank T is connected to the discharge pipe.

The passage 23 further includes a hollow hole 2 outside the first piston portion 13.
The first oil chamber 26 and the second oil chamber 27, which is the hollow hole 2 outside the second piston portion 14, communicate with the orifice throttles 36, 37 provided in the valve housing 1 through passages interposed therebetween. I have.

The downstream passage of the orifice throttle 36 communicates with the oil tank T via the first electromagnetic pressure control valve 51, and the downstream passage of the orifice throttle 37 communicates with the oil tank T via the second electromagnetic pressure control valve 52. I have.

In the above-mentioned flow control valve device, the valve spool 4 is controlled by the signal oil pressure to the first oil chamber 26 and the second oil chamber 27 controlled by the first electromagnetic pressure control valve 51 and the second electromagnetic pressure control valve 52.
Is displaced, and the opening areas of the slits 10, 10, 12, and 12 are changed by the first land portion 15 and the second land portion 16, thereby controlling the supply and discharge of the hydraulic oil to and from the hydraulic cylinder C for suspension of the vehicle and the flow rate thereof. I do.

[Problems to be solved by the invention]

Then, the flow rate of the oil is controlled by the above-mentioned flow control valve device from the hydraulic cylinder C where the hydraulic pressure is always present, and the oil tank which is a no-load portion in the pipeline in which the fixed throttle 25a intervenes from the passage 25. When flowing to T, the back pressure does not rise sufficiently at a low flow rate due to the fixed throttle, so that cavitation cannot be prevented. Is too high, so that a required flow rate cannot be secured due to characteristics.

[Means for solving the problem]

A flow control valve device according to the present invention includes a supply passage connected to a pump, a supply / discharge passage connected to a hydraulic device, and a discharge passage connected to a tank. A flow control valve for switching communication with the passage, and a relief valve connected to the discharge passage of the flow control valve and having a variable throttle whose opening degree changes in proportion to the magnitude of oil pressure from the discharge passage. ing.

(Operation)

The above-mentioned flow control valve device controls a discharge flow rate of pressurized oil from a hydraulic device such as a hydraulic cylinder to a tank by a control signal or a control operation. A predetermined back pressure is maintained by the relief valve irrespective of the flow rate of the discharged oil whose flow rate is controlled.

〔Example〕

 An embodiment of the present invention will be described with reference to the drawings.

As an example of a flow control valve device, switching between supply and discharge of oil to a hydraulic suspension cylinder of an automobile,
A flow control spool valve device (a three-port two-way flow control valve) for performing flow control is shown in FIGS. 1 and 2.

In the following description, up, down, left, and right are directions in FIGS. 1 and 2.

In FIG. 1, a valve sleeve 3 having a length of about half of the hollow hole 2 is fitted and fixed to the right half of the hollow hole 2 of the valve housing 1, and a valve spool 4 is further mounted on the valve sleeve 3 in the axial direction. Is slidably fitted in The left end of the hollow hole 2 is a cup-shaped screw cover 5 screwed to the valve housing 1 in an adjustable manner.
, The right end is the lid plate 6 attached to the valve housing 1.
Are sealed and closed.

On the outer peripheral surface of the valve sleeve 3, annular grooves 7, 8, 9 are formed at three positions at intervals in the axial direction, and each annular groove 7, 8, 9 is formed.
A plurality (two in the example in the figure) of slits 10, 10; 11, 1 penetrating in the radial direction from the bottom of the valve sleeve 3 toward the inner peripheral surface of the valve sleeve 3.
1; 12,12 are formed equally on the circumference. Each slit 10,1
0; 11,11; 12,12 have a rectangular cross section.

The valve spool 4 is provided with a first piston portion 13, a second piston portion 14, a first land portion 15, a second land portion 16 at both ends, and a first annular groove portion 17 and a second annular groove portion 18 therebetween. ing. The first piston portion 13 side of the valve spool 4 (first
The end (left side in the figure) forms an extension 19 and projects into the hollow hole 2. A flanged nut portion 20 is screwed to the tip of the extension portion 19, and one surface of the flange of the flanged nut portion 20, the end surface of the valve sleeve 3, the other surface of the flange of the flanged nut portion 20, and the cup-shaped screw cap 5. Compression coil springs 21 and 2
2 is fitted.

Slits 10,10; 12,12 of valve sleeve 3 and valve spool 4
The first land portion 15 and the second land portion 16 are formed so as to have zero lap when neutral. That is, the opposing edges of the slits 10, 10 and the slits 12, 12 coincide with the opposing peripheral edges of the first land portion 15 and the second land portion 16 in the neutral state.

The valve housing 1 is formed with respective passages 23, 24, 25 communicating with the annular grooves 7, 8, 9 of the valve sleeve 3, a pump P is provided in the passage 23, and a hydraulic cylinder for suspension of a vehicle is provided in the passage 24. C are connected by pipes, respectively, and the oil tank T is connected to the passage 25 by a pipe in which a relief valve 40 shown in FIG. 2 is interposed.

The passage 23 further includes a hollow hole 2 outside the first piston portion 13.
The first oil chamber 26 and the second oil chamber 27, which is the hollow hole 2 outside the second piston portion 14, communicate with the orifice throttles 28, 29 provided in the valve housing 1 through passages interposed therebetween. I have.

The above-described spool valve device is provided for each wheel of the hydraulic suspension of the vehicle, but the pump P and the oil tank T are shared, and the relief valve 40 is interposed in the common oil drain line to the oil tank T.

The relief valve 40 is, as shown in FIG.
41, a hollow hole 42 and a passage 43 penetrating the hollow hole 42 in a direction perpendicular to the hollow hole 42 are formed, a valve sleeve 44 is fitted and fixed to the hollow hole 42, and a valve spool 45 has an axial line It is slidably inserted in the direction. A screw cap 46 is screwed into the right end of the valve sleeve 44.

At the left end of the valve sleeve 44, a plurality of (two in the example in the figure) slits 44a, 44a penetrating in the radial direction are formed at equal circumferential intervals, and the slits 44a, 44a pass through the hollow holes 42 through the hollow holes 42. Four
Communicates with 3.

A land portion 45a at the left end and an annular groove 45b adjacent to the land portion 45a are formed on the valve spool 45, and a compression coil spring 47 is fitted between the right end of the valve spool 45 and the inner surface of the cap 46. I have.

The left end of the hollow hole 42 of the valve housing 41 is connected to the passage 25 of the valve housing 1 of the flow control spool valve device by a pipe, and the passage 43 is connected to the oil tank T by a pipe. Thus, the land portion 45a of the valve spool 45 and the slits 44a, 44a of the valve sleeve 44 form a variable throttle in the communication relationship between the left end side of the hollow hole 42 of the valve housing 41 and the passage 43. That is, the throttle changes in proportion to the magnitude of the oil pressure from the passage 25 of the flow control spool valve device.

Then, the first electromagnetic pressure control valve 51 and the second electromagnetic pressure control valve 52 are provided in the valve housing 1 of the spool valve device, and the first electromagnetic pressure control valve 51 is provided downstream of the orifice throttle 28. The downstream passages of the orifice throttle 29 communicate with the oil tank T via the second electromagnetic pressure control valve 52.

The first electromagnetic pressure control valve 51 and the second electromagnetic pressure control valve 52 have the same configuration as shown in FIG.

In the first electromagnetic pressure control valve 51 and the second electromagnetic pressure control valve 52, a hollow 55 formed in a valve main body 53 erected on the valve housing 1 has a sleeve 55 having a length approximately half the length of the hollow hole 54. A valve rod 56 is slidably inserted in the sleeve 55 in the axial direction, and a needle valve 57 is attached to the lower end of the valve rod 56.
Is fixed. Needle valve 57 due to vertical movement of valve stem 56
Is adapted to come into contact with and separate from the throttle valve seat 58.

The upper end of the hollow hole 54 has a stepped portion 59 formed therein to form a small-diameter hole, and is closed by a screw cap 61 attached to the valve main body 53 with an adjustment nut 60.

A plunger 62 slidable in the hollow hole 54 is fixed to the projecting upper end of the valve stem 56, and a compression coil spring 63 is fitted between the upper end of the valve stem 56 and the screw cap 61. ing.

A solenoid 64 is attached so as to surround the outer periphery of the valve body 53, and a solenoid cover 65 is attached so as to surround the outer periphery of the solenoid 64. An exciting current according to the state of the external hydraulic suspension is supplied to the solenoid 64.

At least the valve body 53, the sleeve 55, the plunger 62, and the solenoid cover 65 are made of a magnetic material and form a magnetic force line passage.

The operation of the above-mentioned flow control spool valve device will be described.

The first electromagnetic pressure control valve 51 is provided by an external control device (not shown).
When a control signal current is supplied to each solenoid 64 of the second electromagnetic pressure control valve 52 and the solenoid 64 is excited, a magnetic field line passing through a magnetic field line passage of the valve body 53 or the like, which is a magnetic material, is formed in response to the control signal current. Attraction force corresponding to the magnitude of the control signal current acts between the step portion 59 of the main body 53 and the end face of the plunger 62. In other words, the needle valve 57 is pressed against the throttle valve seat 58 with a force obtained by reducing the spring force of the compression coil spring 63, which is the initial set relief pressure, by the attraction force corresponding to the magnitude of the control signal current.
A relief pressure according to the magnitude of the control signal current is obtained.

The initial set relief pressure of each of the first electromagnetic pressure control valve 51 and the second electromagnetic pressure control valve 52 is adjusted by adjusting the distance between the tip of the screw cap 61 and the upper end of the valve rod 56 by the adjustment rotation of the adjustment nut 60. That is, it is adjusted by adjusting the preload of the compression coil spring 63.

Then, the pressure oil from the pump P supplied to the first oil chamber 26 and the second oil chamber 27 through the passage 23 and the orifice throttles 28 and 29 partially receives the first electromagnetic pressure control valve 51 and the second electromagnetic pressure. The oil is discharged to the oil tank T through the pressure control valve 52 and adjusted to the respective set pilot pressures. After all, the first electromagnetic pressure control valve 51
The pressure oil of the pilot pressure adjusted according to the magnitude of the control signal current to the second electromagnetic pressure control valve 52 is supplied to the first oil chamber 26 and the second oil chamber 26.
Since it is supplied to the oil chamber 27, the valve spool 4 is displaced in the axial direction according to the difference between the two control signal currents.

In the neutral state, the compression coil springs 21 and 22 are in an equilibrium state, and the oil pressure of the first oil chamber 26 and the oil pressure of the second oil chamber 27 cause the valve spool 4 to be in the zero wrap state and the slits 11 and 1
1 is in a state of being cut off from the slits 10, 10; 12, 12 on both sides,
The hydraulic cylinder C is shut off by both the pump P and the oil tank T.

When a predetermined amount of hydraulic oil is supplied to the hydraulic cylinder C to which a constant pressure is constantly applied, a control signal current required for the solenoids 63 of the first electromagnetic pressure control valve 51 and the second electromagnetic pressure control valve 52 from an external control device. Is supplied, first, the hydraulic pressure becomes the second
The height of the valve spool 4 rises toward the oil chamber 27, and the valve spool 4 first presses the compression coil spring 22 by one surface of the flange of the flanged nut portion 20 and moves leftward.

Thus, the slits 10 and 10 are opened to an opening area corresponding to the control signal current, and the pressure oil from the oil pump P passes through the passage 2.
3. While being supplied to the hydraulic cylinder C through the slits 10, 10, the slits 11, 11, and the passage 24, the slits 12, 12 are closed, and the passage 25 to the oil tank T is also shut off.

Then, after the hydraulic cylinder C operates by a predetermined amount, the flow control spool valve device is returned to the neutral state.

When a predetermined amount of pressure oil is discharged from the hydraulic cylinder C, a necessary control signal current is supplied from an external control device to each solenoid 64 of the first electromagnetic pressure control valve 51 and the second electromagnetic pressure control valve 52. , The hydraulic pressure of the first oil chamber 26 is higher,
The valve spool 4 first presses the compression coil spring 21 by the other surface of the flange of the flanged nut portion 20 and moves rightward.

This time, the slits 12 and 12 are opened to an opening area corresponding to the control signal current, and the pressure oil from the hydraulic cylinder C flows through the passage 2.
4, the oil is discharged into the oil tank T through the slits 11, 11, the slits 12, 12, the passage 25, and the relief valve 40, and the passage 23 from the oil pump P is kept closed while the slits 10, 10 are closed.
Also remain blocked. Then, after the hydraulic cylinder C is operated in the reverse direction by the predetermined amount, the flow control spool valve device is returned to the neutral state.

In the operation of the above-mentioned flow control spool valve device, the passage
When the discharge flow rate of the pressurized oil from the valve 25 is constant, the hydraulic pressure applied to the left end surface of the land 45a of the valve spool 45 of the relief valve 40 is small, and the valve spool 45 moves to the left due to the spring force of the compression coil spring 47. The opening degree of the slit 44a of the valve sleeve 44 is reduced by the land 45a of the valve spool 45. When the discharge flow rate of the pressure oil is high, the hydraulic pressure applied to the left end face of the land 45a of the valve spool 45 is large, and the spool 45 is displaced rightward against the spring force of the compression coil spring 47, and The slit 4 of the valve sleeve 44 is formed by the land 45a of the spool 45.
The aperture of 4a is expanded.

As a result, in the operation of the above-described flow control spool valve device, when the discharge flow rate of the pressure oil from the passage 25 is a low flow rate, the relief valve 40 is throttled, and the back pressure necessary for preventing cavitation is secured, For high flow rate, relief valve
40 is opened to prevent back pressure from increasing. That is,
In a flow control spool valve device that switches between supply and discharge of oil to a hydraulic cylinder and controls flow for hydraulic cylinders for all hydraulic suspensions, a common relief is used regardless of the flow rate of pressure oil discharged from passages 25, 25 ... The back pressure is always maintained as required by the valve 40.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to the flow control valve apparatus of this invention, in the flow control discharge of the pressure oil from a pressure part to a no-load part, the back pressure is always maintained at a required constant regardless of the discharge flow rate. Therefore, it is possible to prevent cavitation causing noise and prevent an excessive increase in back pressure, thereby securing a flow rate necessary for characteristics.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional front view of a flow control spool valve device according to an embodiment of the present invention, FIG. 2 is a cross-sectional front view of a relief valve in FIG. 1, and FIG. It is a partial section front view of a valve device. 1,41: valve housing, 2, 42, 54: hollow hole 3, 44: valve sleeve, 4, 45: valve spool 5: cup-shaped screw lid, 6: lid plate 7, 8, 9, 45a: annular groove, 10, 11, 12, 44a: slit 13: first piston portion, 14: second piston portion 15: first land portion, 16: second land portion 17: first annular groove portion, 18: second annular groove portion 19: Extension part, 20: flanged nut part 21, 22, 47, 63: compression coil spring, 23, 24, 25, 43: passage 26: first oil chamber, 27: second oil chamber 25a, 28, 29: orifice Restrictor, 40: Relief valve 46, 61: Screw cap, 45a: Land part 51: First electromagnetic pressure control valve, 52: Second electromagnetic pressure control valve 53: Valve body, 55: Sleeve, 56: Valve rod, 57 : Needle valve 58: Valve seat, 59: Step, 60: Adjusting nut, 62: Plunger 64: Solenoid, 65: Solenoid cover P: Pump, C: Hydraulic cylinder for suspension, T: Oil tank

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-165432 (JP, A) JP-A-56-21607 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F16K 47/02 F15B 11/00-11/22 F15B 13/06

Claims (1)

(57) [Claims] 1. A supply passage connected to a pump, a supply / discharge passage connected to a hydraulic device, and a discharge passage connected to a tank, wherein the supply passage, the discharge passage, and the supply / discharge passage are provided by displacement of a valve spool. A flow control valve configured to switch communication with the discharge passage, and a relief valve connected to the discharge passage, the relief valve including a variable restrictor whose opening degree changes in proportion to the magnitude of oil pressure from the discharge passage. apparatus.